More particularly, it relates to such dispensers of a kind in which there is a dispensing chamber for containing a quantity of the workpieces and means are provided for blowing compressed air into the dispensing chamber so as to create a turbulence which agitates the workpieces such that some of the workpieces become entrained in the air flow and are discharged singly from the dispensing chamber, together with the compressed air, through one or more outlet openings.
One prior art example of a dispenser of the above kind is that disclosed in United Kingdom Pat. No. 1281523 in which the dispensing chamber is provided by an upright cylindrical vessel and means are provided for blowing intermittent jets of compressed air vertically upwards into the chamber, through the central region of the bottom end and through the workpieces therein, to create the turbulence which agitates and carries the workpieces upwards in random motion and causes some of them to discharge through an outlet in the upper part of the chamber.
Such devices are especially useful for dispensing small helical coil springs because, although these usually tend to entangle together such as to make handling difficult, the impacts to which they are subjected in a dispenser of the kind referred to can perform a useful and efficient separating function.
Thus, another prior art dispenser of the kind referred to, especially designed for the above purpose of entangling small helical coil springs, is that disclosed in U.S. Pat. No. 3346305. In this case, it was proposed to introduce the compressed air horizontally into a tilted cylindrical vessel in a direction oblique to a diameter so as to produce an upwardly moving vortex swirling about a substantially vertical axis to agitate and separate the springs and to lift them in a spiral path up to a discharge outlet through which they are guided with an abrupt change of direction in their movement by adjacent deflector means.
It has been realised, however, that there is scope for improvement in such prior art dispensers, both in respect of their physical structural form and their potential operating efficiency.